1. Field of Invention
Embodiments of the invention relate generally to electronic devices and, more specifically, to electronic devices having multi-transistor cells.
2. Description of Related Art
Many types of electronic devices include data cells with a single transistor. Typically, the transistor controls whether a stimulus (e.g., a current or voltage) is applied to, or by, a data element (e.g., a memory element, an imaging element, or other device configured to output data, such as various kinds of sensors). Often a large number of data elements are disposed in an array, and the transistor allows individual data elements in the array to be selected. For example, certain types of dynamic random access memory (DRAM) include both a capacitor, which functions as a data element, and a single transistor connected to the capacitor. The capacitor usually stores data by storing a charge that is representative of data (e.g., a 0 or a 1 in a single-bit device, or a 00, 01, 10, or 11 in a two-bit device), and the transistor typically controls access to the capacitor by controlling the flow of current to and from the capacitor, allowing current to flow during reading and writing and preventing current from flowing when retaining data. In another example, some non-volatile memory devices include a single transistor connected to a body of phase-change material. Typically, the phase-change material stores data by assuming a more or less ordered state, e.g., a crystalline or amorphous state, that corresponds with a data value. The data value may be read by sensing the state of the phase-change material, typically by conducting a current through the phase-change material and sensing its resistance. The current is generally controlled by the transistor. In each of these examples and many others, the data element is connected to a single transistor that affects the flow of data to or from the data element.